Angioscopy apparatus and methods

ABSTRACT

The present invention includes a fluid delivery device capable of delivering perfusion or other fluids to a vascular site. Preferred embodiments permit delivery of large quantities of fluid without causing recoil of the device, and without causing trauma to the vascular site.

RELATED APPLICATION

The present application is a divisional of application Ser. No.08/669,662, filed Jun. 24, 1996, U.S. Pat. No. 5,957,899 entitled "HighPressure Transluminal Fluid Delivery Device", which is a continuation inpart of Application Ser. No. 08/563,057, filed Nov. 27, 1995, now U.S.Pat. No. 5,797,876 entitled "High Pressure Perfusion Device".Application Ser. No. 08/563,057 is incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates generally to medical devices for thedelivery of fluids transluminally, and more particularly to a highpressure perfusion device capable of delivering fluids atraumatically.

BACKGROUND

Various medical procedures require fluids to be delivered to specificlocations within the body, typically via a fluid delivery catheter. Anarrow steerable guidewire is often used to maneuver through narrow,tortuous, and/or branching body passageways. After the guidewire hasbeen directed to the desired location, a fluid delivery catheter may beinserted over the guidewire. The guidewire is usually removed beforefluid delivery begins. Guidewires which are themselves capable of fluiddelivery (such as that disclosed in U.S. Pat. No. 5,322,508) are alsoknown in the art.

In current angiographic procedures, a relatively large (5 French (1.65mm) or larger) catheter is used to inject a contrast material intovascular spaces, such as the coronary arteries and cerebral vessels.Contrast material is a radiopaque liquid typically including iodine oran equivalent component, and having a viscosity 2-10 times that ofwater. During or after injection of the radiopaque contrast material, anx-ray or fluoroscopic image is taken of the injection site.

Large angiographic catheters are typically required to perform suchprocedures because of the relatively high viscosity of commonly usedcontrast materials, and because of the relatively large amount ofcontrast material required to produce a good quality angiographic image.But even when relatively large catheters are used, the contrast materialmust be delivered under high pressure to ensure that a sufficientquantity of contrast material is delivered.

When contrast material is injected at a rate necessary to performcoronary angiography selectively into either the right or left coronaryartery, the relatively high velocity associated with the injectionfrequently results in recoil of the catheter, so that the contrastmaterial may be injected into the aorta rather than selectively into thecoronary artery. The relatively high velocity of contrast materialinjection also increases the potential for inducing mechanical trauma tothe inner surface of a blood vessel. Accordingly, angiographic catheterssmaller than about 5 French are not ordinarily suitable for use in suchprocedures because of the even higher velocities required to inject asufficient quantity of contrast material.

The use of conventional angiographic catheters presents other problemsas well. For example, a guidewire is usually needed to advance thecatheter from the peripheral arterial access site to a location ofinterest. This guidewire is then removed from the lumen of the catheterto allow the injection of contrast material through the same lumen. Theuse of both a wire and a catheter requires time for preparation andremoval, and the overall cost of the equipment is increased by the needfor two devices for each procedure. Moreover, in coronary angiographicprocedures, the right and left coronary arteries usually requirecatheter tips having different shapes to facilitate engagement of theostium of the coronary artery with the distal tip of the catheter.

Accordingly, there remains a need in the art for an inexpensive, lowprofile, easy to use catheter or fluid delivery device that can deliverlarge amounts of contrast material without causing trauma to vascularwalls, and without causing recoil of the catheter itself.

In angioscopy procedures, a fiberoptic angioscope positioned with aguide catheter is used to image the interior of a blood vessel. Toproduce a clear image, the blood within the vessel is displaced, usuallywith a transparent saline solution. Current angioscopy products, such asthe ImageCath® coronary angioscope by Guidant Corporation, include anangioscope within an outer catheter that provides a balloon to stopantegrade blood flow, and saline to displace blood within a vessel.

While the Guidant device works for its intended purpose, the relativelylarge profile of the outer catheter (4.5 French, or approximately 1.5mm) requires the use of a very large (8 French, or approximately 2.6 mm)guide catheter to deliver the Guidant device to the desired location.The requirement for such a large guide catheter makes the Guidantangioscope difficult or impossible to use in certain locations, such asnarrow or tortuous vessels. Accordingly, there remains a need in the artfor a low profile angioscopy device that can be used to image areasaccessible through narrow or tortuous blood vessels.

During balloon angioplasty procedures, a catheter equipped with a smallballoon is inserted (usually over a guidewire) into an artery that hasbeen narrowed, typically by the accumulation of fatty deposits. Theballoon is then inflated to clear the blockage or lesion and widen theartery. Upon balloon inflation, blood flow distal to (that is,"downstream" from) the inflated balloon may be almost completelystopped.

Myocardial ischemia (that is, a reduction in blood perfusion to theheart muscle) occurs transiently in the majority of patients undergoingcoronary angioplasty procedures, such as balloon angioplasty,directional atherectomy, rotational atherectomy, and stent deployment.The permissible duration of occlusion due to balloon inflation or otherdevice deployment is normally determined by the severity of myocardialischemia. Typically, evidence of severe ischemia (including patientchest pain and ECG changes) requires that the operator deflate theballoon or remove the occlusive device after approximately 60 to 120seconds. For anatomically difficult lesions, such as type B and Clesions, longer periods of balloon inflation (or other devicedeployment) are frequently desirable for the first balloon inflation orother device deployment.

Autoperfusion balloon catheters, and catheters of the type disclosed inU.S. Pat. No. 5,322,508, can in some circumstances allow longer periodsof balloon inflation. However, the blood (or other physiologic liquid)flow through such devices is frequently insufficient to provide anadequate oxygen supply to tissues distal to the angioplasty balloon orother occlusive device.

Recent advances in the generation and application of oxygensupersaturated solutions have made it possible to deliver greateramounts of oxygen to tissues distal to an angioplasty balloon. U.S. Pat.No. 5,407,426, and pending application Ser. Nos. 08/273,652, filed Jul.12, 1994, entitled "Method for Delivering a Gas-Supersaturated Fluid toa Gas-Depleted Site and Use Thereof"; 08/353,137, filed Dec. 9, 1994,entitled "Apparatus and Method of Delivery of Gas-SupersaturatedLiquids"; 08/453,660, filed May 30, 1995, entitled "Method forDelivering a Gas-Supersaturated fluid to a Gas-Depleted Site and UseThereof"; 08/465,425, filed Jun. 5, 1995, entitled "Method for Deliveryof Gas-Supersaturated Liquids"; 08/484,279, filed Jun. 7, 1995, entitled"Apparatus and Method of Delivery of Oxygen-Supersaturated PhysiologicSolutions During Clinical Procedures"; and 08/484,284, filed Jun. 7,1995, entitled "High Pressure Gas Exchanger", which are incorporatedherein by reference, disclose various methods for the generation andapplication of oxygen supersaturated liquids.

As is described in the above referenced patent applications, thegeneration, transport and delivery of oxygen supersaturated liquid mayrequire the application of very high hydrostatic pressures. Accordingly,there remains a need for a high pressure fluid delivery device capableof infusing bubble-free fluid, which is supersaturated with oxygen, tovessels or ducts through and beyond the central lumen of a balloonangioplasty catheter or similarly occlusive device.

SUMMARY

Preferred embodiments of the present invention meet the above needs inthe art by providing a guidewire device capable of delivering fluids toa vascular site, while at the same time exhibiting handlingcharacteristics associated with existing non-perfusion guidewires sothat additional education or retraining of operators is reduced oreliminated.

Preferred embodiments of the invention further meet these needs byproviding a relatively low profile fluid delivery device capable ofdelivering relatively large quantities of contrast material or otherfluid to a desired vascular location without causing trauma to thevasculature, and without causing significant recoil of the deliverydevice.

Preferred embodiments of the present invention also provide a perfusionguidewire which closely matches the dimensions and physicalcharacteristics of standard guidewires in diameter, length, flexibility,column strength, torque transfer, surface friction, kink resistance,radiopacity (i.e., opacity to x-rays), non-thrombogenicity (i.e.,tendency not to promote blood clots) and bio-compatibility. Preferredembodiments of the invention permit high pressure perfusion of anydesirable liquid, and also include a liquid flow path that will notpromote bubble generation or growth, or destabilize an oxygensupersaturated solution.

A high pressure perfusion guidewire according to the inventionpreferably includes two or three sections: a tubular proximal segment orhandle, which comprises the greater part of the perfusion guidewirelength; an (optional) transitional region which provides the desiredtorque transfer and pressure drop characteristics; and a distal segmentwhich conveys the fluid out of the perfusion guidewire at a relativelylow velocity, and also mimics the distal functions of a standardguidewire.

The proximal segment may be connected to a fluid source using standardor specialized connectors capable of withstanding the required fluidpressures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a transluminal fluid delivery system including a highpressure perfusion device according to a preferred embodiment of theinvention;

FIG. 2 is a cross sectional view of the proximal portion of a highpressure perfusion device according to the invention;

FIG. 3 is a cross sectional view of the transitional region of a highpressure perfusion device according to the invention, continued fromFIG. 2;

FIG. 4 is a cross sectional view of the transitional region of analternative embodiment of a high pressure perfusion device according tothe invention, also continued from FIG. 2;

FIG. 5 is a cross sectional view of the transitional region of a secondalternative embodiment of a high pressure perfusion device according tothe invention, also continued from FIG. 2;

FIG. 6 is a partial cross sectional view of the distal segment of a highpressure perfusion device according to the invention, continued fromeither of FIGS. 3, 4 or 5;

FIG. 7 is a partial cross sectional view of the transitional region anddistal segment of an alternative perfusion device according to theinvention;

FIG. 8 is a partial cross sectional view of circled portion 150 of thedistal segment shown in FIGS. 7 and 14;

FIG. 9 is a partial cross sectional view of the transitional region anddistal segment of a second alternative perfusion device according to theinvention;

FIG. 9A is a partial cross-sectional view of the transitional region ofFIG. 5 and the distal segment of FIG. 9, combined in a furtheralternative perfusion device according to the invention;

FIG. 10 is a partial cross sectional view of circled portion 139 of thedistal segment shown in FIG. 9;

FIG. 11 is a partial cross sectional view of the transitional region anddistal segment of a third alternative perfusion device according to theinvention;

FIG. 12 is a partial cross sectional view of circled portion 137 of thedistal segment shown in FIGS. 11 and 20;

FIG. 13 is a partial cross sectional view of circled portion 112 of thetransitional region shown in FIGS. 7, 9, and 11;

FIG. 14 is a partial cross sectional view of the transitional region anddistal segment of a fourth alternative perfusion device according to theinvention;

FIG. 15 is a partial cross sectional view of circled portion 114 of thedistal segment shown in FIG. 14;

FIG. 16 is a partial cross sectional view of the transitional region anddistal segment of a fifth alternative perfusion device according to theinvention;

FIG. 17 is a partial cross sectional view of circled portion 148 of thetransitional region shown in FIG. 16;

FIG. 18 is a partial cross sectional view of the distal segment of asixth alternative perfusion device according to the invention;

FIG. 19 shows a reconfigurable fluid delivery device and associatedhardware according to a preferred embodiment;

FIG. 20 is a partial cross sectional view of the distal segment of thereconfigurable fluid delivery device of FIG. 19; and

FIG. 21 is a partial cross sectional view of a guide catheter containingthe distal segment of the perfusion device shown in FIG. 18 and anangioscopic optical bundle.

DETAILED DESCRIPTION

The structure and function of the preferred embodiments can best beunderstood by reference to the drawings. The reader will note that thesame reference numerals appear in multiple figures. Where this is thecase, the numerals refer to the same or corresponding structure in thosefigures.

The present invention includes several embodiments of a high pressurefluid delivery device. As will be made clear below, the majordifferences between the various embodiments are in the transitionalregions and distal segments. Persons of ordinary skill in the art willunderstand that the alternative regions or segments may be used togetherin combinations other than described in detail below, based on theteachings contained herein.

Transluminal Fluid Delivery System

FIG. 1 shows a transluminal fluid delivery system 100 according to apreferred embodiment. Fluid delivery system 100 includes a high pressuresource 102, such as a pump or reservoir, a connector 70, a tube 104connecting an output of high pressure source 102 to an input ofconnector 70, and a perfusion device or guidewire 108. Connector 70 maybe a standard or specialized connector capable of withstanding thedesired fluid pressures. As will be discussed further below, eachembodiment of perfusion guidewire 108 includes a handle or proximalsegment 10, a transitional region 20, and a distal segment 40.

Proximal Segment or Handle

Referring now to FIG. 2, a handle or proximal segment 10 of perfusionguidewire 108 is shown. Proximal segment 10 includes a thin-walled tube12 which defines a lumen. Tube 12 is made of bio-compatible material,has the appropriate dimensions, and the appropriate burst strength,flexibility, torque transfer, and kink resistance characteristics foruse as a perfusion device or guidewire as described herein. Tube 12 ispreferably coated over most of its length with a low friction, thin filmbio-compatible coating 13, such as PTFE. Tube 12 also has an opening 16for connection to a source of high pressure liquid, such as contrastmaterial, saline, or oxygen supersaturated liquid.

In one embodiment which may be used as a perfusion guidewire, tube 12 ofproximal segment 10 is preferably a 304 stainless steel tube having a0.0145" outside diameter, a 0.010" inside diameter, and a length ofapproximately 150 cm. Tube 12 preferably also has a 0.0004" to 0.0007"thick coating 13 of PTFE over its full length, except for a few cm ateach end. In another embodiment, tube 12 of proximal segment 10 is a 304stainless steel tube having a 0.0132" outside diameter, a 0.008" insidediameter, and a length of approximately 150 cm. In this embodiment, tube12 would also preferably have a 0.0004" to 0.0007" thick coating of PTFEover its full length, except for a few cm at each end. If necessary toavoid kinking during the initial part of a procedure, a support wire orstylet (not shown) may be inserted in tube 12. The support wire orstylet may be withdrawn before liquid is introduced into tube 12.

Transitional Region

Referring now to FIG. 3, one embodiment of a transitional region 20 ofperfusion device or guidewire 108 is shown. Transitional region 20provides a transition between tube 12 and the region defined by corewire 24 and sheath 26. The transitional region 20 also is designed toachieve the objective of providing a perfusion guidewire with thehandling characteristics of a "standard" guidewire. "Standard" guidewireis used herein to refer to the typical non-perfusion guidewires commonlyused today for various procedures. Such procedures may involve coronaryor peripheral vessels. Examples of guidewires considered to be standardguidewires are shown in U.S. Pat. Nos. 4,538,622 and 4,619,274. Based onthe teachings contained herein, a person of ordinary skill in the artmay select the various parameters of the present invention to achievehandling characteristics substantially the same as those of the aboveguidewires, or any other handling characteristics desired for aparticular procedure.

In one embodiment, the distal end of tube 12 is ground or otherwisemachined eccentrically so that a tapered lip 28 is created whichresembles the nib end of a quill pen. Alternatively, a separate lip maybe secured to the end of the tube. By way of example, for the tube 12dimensions described above, lip 28 is preferably between about 1 and 5cm long, and is preferably tapered smoothly to a final dimension ofabout 0.006" wide and about 0.001" thick. This "quill-like" lip 28provides several advantages.

First, lip 28 provides a low resistance transition, since the transitionfrom tube 12 to the region defined by core wire 24 and sheath 26 isaccomplished with little or no decrease in cross-section flow area, andin some instances even net increase. Second, lip 28 provides a smoothflow transition because lip 28 is tapered; there are no abrupt changesin the flow path geometry. These first two characteristics reduce thepossibility that cavitation or bubble formation will take place in asupersaturated solution flowing through the guidewire. As a thirdadvantage, lip 28 provides a convenient and strong attachment point forthe distal core wire 24. Finally, lip 28 provides a joint between corewire 24 and tube 12 which creates a smooth transition in terms offlexibility and stiffness. The taper of lip 28 may be easily adjusted tomatch any desired flexibility profile. In particular, the taper may beadjusted to match the flexibility profile of a standard coronaryguidewire.

An important element of guidewire design involves the transfer of torquefrom the proximal end of the guidewire, where the physician manipulatesthe guidewire, to the distal end. A smooth, even rotary action isrequired of a guidewire, even in a tortuous vascular pathway. Becauselip 28 is not axially symmetric, it can exhibit a "cast" or unevennessin rotary motion when it is passed over a sharp bend. To reduce thecast, lip 28 is preferably sufficiently short in length and core wire 24is long enough such that lip 28 is positioned proximal of any sharpbends in the vascular pathway during use. In practice, it is usuallysufficient to locate lip 28 proximal of the aortic arch during acoronary angioplasty procedure.

Referring now to FIG. 4, an alternative embodiment of transitionalregion 20 is shown. In procedures where transitional region 20 mustencounter vascular tortuosity, or it is otherwise desirable to greatlyreduce the cast, a lip 28A may be fashioned from the distal end of tube12 into a helical form. Lip 28A will exhibit more evenness in rotarymotion when passed over sharp bends than lip 28, but lip 28A will stillmaintain the aforementioned advantages of the non-helical lip 28.Exemplary dimensions for lip 28A with the tubes described above areabout 5 cm long, and tapered smoothly to a final dimension of about0.006" wide and about 0.001" thick.

Referring now to FIG. 5, a second alternative embodiment of transitionalregion 20 is shown. In the embodiment shown in FIG. 5, the distal end oftube 12 is preferably ground or fashioned so that the outside diameterof tube 12 is reduced, while the inside diameter of tube 12 remainssubstantially the same. This forms a step 260 having a substantiallyannular opening 240 defined by the inside diameter of step 260 and corewire 24. A sheath 26 is preferably attached to the reduced outsidediameter of tube 12 along step 260 using a layer of epoxy 200. Step 260facilitates the attachment of sheath 26 while maintaining an outsidediameter that is substantially the same along the length of the device.Alternatively, step 260 could be eliminated and sheath 26 could beattached directly to the outside of tube 12.

Core wire 24 is ground at its proximal end to form an entrance taper 25including a proximal extension 25A. Proximal extension 25A of core wire24 is fixed to a notch 262 in tube 12 using an appropriate solder orbraze alloy 264.

Step 260 preferably has an outside diameter of about 0.012", andproximal extension 25A preferably is 0.120" long and has a diameter of0.0057". Entrance taper 25 preferably has a diameter that ranges from0.0055" to 0.0075".

Distal Segment

FIG. 6 shows one embodiment of a distal segment 40 of perfusionguidewire 108. Distal segment 40 includes core wire 24, thin-walledsheath 26 and a distal coil or coil spring 42. The material propertiesand dimensions of distal segment 40 are preferably selected to match thephysical properties of standard guidewires.

In an exemplary embodiment, sheath 26 comprises approximately 30 cm ofhigh strength polymer tubing 54, having an outside diameter of about0.0145", an inside diameter of about 0.0135", and approximately 4 cm ofpolyester heat shrink tubing 56 in the transitional and proximal regions(See FIGS. 2-4) having an approximate, unrecovered inside diameter of0.017" and a wall thickness of about 0.0005". Tubing 54 is preferablymade of polyimide. At the proximal end of sheath 26, the polyimidetubing 54 is placed over lip 28 or 28A, to within 1 cm of the proximalend of lip 28 or 28A. Polyester heat shrink tubing 56 forms a bridgingjoint between tube 12 and polyimide tubing 54. A thin epoxy film (notshown) is applied beneath heat shrink tubing 56, and then heat shrinktubing 56 is heat sealed to form a leak-free bond with tubing 12 andpolyimide tubing 54.

In alternative embodiments (shown, for example, in FIG. 5), sheath 26comprises approximately 35 cm of high strength polymer (preferablypolyimide) tubing 54, having an outside diameter of about 0.0145" and aninside diameter of about 0.0135". At the proximal end of sheath 26,tubing 54 is placed over step 260. A thin epoxy film is applied beneathpolyimide tubing 54 to form a leak-free bond with step 260.

The polyimide tubing 54 is preferably coated with a thin film of alubricous hydrophilic coating. Appropriate hydrophilic coatings, such asBSI PV01/PVP, are well known to those skilled in the art.

At its distal end, polyimide tubing 54 of sheath 26 may be open- orclose-ended. If polyimide tubing 54 is close-ended, it may be configuredwith a number of sideports 55 or some such means to allow flow to exitsheath 26. The sideports 55 can be made as a plurality of perforationswhich are typically between about 15-50 μm in diameter, arranged alongabout a 2 cm length. The open end 52 of polyimide tubing 54 may bepositioned over distal coil 42, or it may terminate before coil 42 as isshown in FIG. 6. Alternatively, the distal end of polyimide tubing 54may overlap distal coil 42 and be bonded with epoxy to distal coil 42.Polyimide tubing 54 may also be attached to an exposed portion of corewire 24. If polyimide tubing 54 is open-ended, it may be terminated witha bevel or a square cut open end 52, and may also be configured with anumber of sideports 55. The actual configuration of the openings andtotal area can be selected by a person of ordinary skill based on theteachings herein.

As was discussed above, core wire 24 is attached at its proximal end tothe distal end of lip 28 or 28A (see FIGS. 3 and 4) or to notch 262 intube 12 (see FIG. 5). At its distal end, core wire 24 is embedded atleast partially into distal coil 42 as is known in guidewireconstruction. Core wire 24 may have any appropriate cross-sectionalshape, length and diameter.

In an exemplary preferred embodiment, core wire 24 is approximately 35cm long with a circular cross section. Over the proximal 24 cm, corewire 24 has an outside diameter of about 0.006". It then tapers smoothlyover an approximately 2 cm distance to an outside diameter of about0.005", and is constant at this diameter for approximately 5 cm. Corewire 24 then tapers down to an outside diameter of about 0.003", whereit is embedded within distal coil 42. Again, core wire 24 is ground atthe proximal end to form an entrance taper 25 which provides a smoothflow transition (See FIGS. 3, 4, and 5).

Distal coil 42 serves as a compliant leading edge for the atraumatic andformable guidewire. The requirements, construction and dimensions ofdistal coil 42 are well known to those skilled in the art. In apreferred embodiment, distal coil 42 is 4 cm long with an outsidediameter of 0.010" to 0.014". Distal coil 42 is preferably coated with athin film of an appropriate hydrophilic coating such as BSI PV01/PVP.Distal coil 42 is also preferably radiopaque along its distal 2 cm, andmay have a bend or cast at its distal end to allow the physician to"steer" the guidewire along tortuous passageways.

The disclosed perfusion guidewire is preferably inserted and used in thesame manner as a standard coronary guidewire using a conventionaltorquing handle (not shown). As is known to those skilled in the art, atorquing handle is a hollow tube with an annular screw-down clampsimilar to the chuck of a drill. It is slipped over the proximal end ofthe guidewire and screwed down to securely hold the guidewire to allowits manipulation. The preferred embodiments of the invention exhibitsubstantially the same performance characteristics as a standardguidewire, and can be inserted and used with conventionalinstrumentation and techniques. For this reason, a perfusion guidewireaccording to the invention could be regularly substituted for a standardguidewire, so that in the event a perfusion need arises during aprocedure, there is no need to exchange guidewires. In a typicalprocedure using the present invention, the perfusion guidewire isinserted into the patient's vasculature and advanced to the treatmentsite using known techniques. This might involve crossing a lesion forapplication of balloon angioplasty. However, unlike standard guidewires,when the vessel is occluded during a procedure, flow in the vessel canbe maintained by perfusing fluid through the guidewire of the presentinvention.

Other Alternative Embodiments

As was discussed above, the present invention includes severalembodiments of perfusion device or guidewire 108. Several alternativeembodiments of transitional region 20 and distal segment 40 will bediscussed below. Also, dimensions provided herein are preferreddimensions for a particular size of device as described. Persons ofordinary skill in the art may appropriately size a device by modifyingthe preferred dimensions without departing from the scope of theinvention.

Transitional Region

As was discussed above with respect to FIGS. 3, 4, and 5, transitionalregion 20 may include an elongated lip 28 or 28A, or a step 260 which isformed from the distal end of tube 12. Alternatively, as is shown inFIGS. 7, 9, 11, and 13, a lip 28C may be formed from a separate tubularsegment 110. Of course, lip 28C could take the form of lip 28 or 28A.

By making lip 28C out of a separate tubular segment 110, the segmentdistal to lip 28C can be made with a substantially smaller outsidediameter than would otherwise be possible if the lip were made from tube12. Circled region 112 in FIGS. 7, 9, and 11 is shown enlarged in FIG.13.

As is shown in FIGS. 14 and 15, tubular segment 110 may also include asecond tapered lip 28D. Lip 28D provides a smooth transition from thelarger inside diameter of tube 12 to the smaller inside diameter oftubular segment 110, and thus minimizes turbulence. Circled region 114of FIG. 14 is shown enlarged as FIG. 15.

Again, lips 28C and 28D may be fashioned into any desired shape. Incases where lip 28C or 28D must encounter vascular tortuosity, one orboth may be fashioned into a helical form, as was discussed above withrespect to FIG. 4. Lips 28C and 28D provide the same advantages asdiscussed above with respect to lips 28 and 28A.

Tubular segment 110 is preferably a 304 stainless steel tube having aninside diameter of 0.005", an outside diameter of 0.0075", and a lengthof 5 cm. Lips 28C (and where applicable 28D), are preferablyapproximately 1 cm long, and are preferably tapered smoothly to a finaldimension of 0.006" wide by 0.001" thick.

In the embodiments shown in FIGS. 7, 9, 11, 13, 14, and 15, tubularsegment 110 is typically joined to tube 12 and to stainless steel coil116 with a lap joint 118 of an appropriate solder or braze alloy.Tubular segment 110 is also sealed with an overcladding or sheath ofpolyimide tubing 54. Polyimide tubing 54 is in turn surrounded bystainless steel coil 116, which preferably has an inside diameter of0.010" and an outside diameter of 0.014". Polyimide tubing 54 can besealed to tubular segment 110 via a leak tight lap bond 122 made ofepoxy.

As in the above described embodiments, a core wire 24 is bonded to thedistal end of lip 28C. Specifically, entrance taper 25 is preferablylap-joined with an appropriate solder or braze alloy to the distal endof lip 28C with an overlap of approximately 1.5 mm. Again, core wire 24may be coated with a thin film of an appropriate hydrophilic coating.

Distal Segment

In the embodiments shown in FIGS. 7, 9, 11, and 14, distal segment 40(i.e., the segment distal to lip 28C) generally includes core wire 24, anonporous entrance region including tubing 54 and coil 116, a porousperfusion zone 125 including a baffle 126, and a standard floppy tipdistal coil 42. Distal coil 42 is preferably separated from coil 116 bya solid solder joint 140. Baffle 126 provides a gradual pressure andflow velocity drop for high pressure fluids being perfused or deliveredat a site of interest.

Fluid flows from transitional region 20 through tubing 54 (and aroundcore wire 24) to baffle 126 in perfusion zone 125. Coil 116, whichsurrounds and supports tubing 54 and baffle 126, allows tubing 54 andbaffle 126 to withstand high hydrostatic pressures.

The perfusion zone 125 is a porous region, preferably about 1-6 cm inlength, through which the perfusion fluid is delivered. To effect"weeping" or low velocity flow, perfusion zone 125 includes porousbaffle 126 surrounded by stainless steel coil 116. In general, porousbaffle 126 can be any suitable structure which causes a flow velocitydrop as the fluid exits, to convert high velocity fluid flow (typicallygreater than 10 m/s) to a low velocity, or "weeping" flow. Baffle 126preferably provides a flow velocity drop of at least a factor of five.The output of a low velocity, or "weeping" flow (as opposed to a flowincluding high velocity jets) from baffle 126 is atraumatic in that itreduces the possibility that fluid delivered by the device or guidewirewill damage nearby tissue. A low velocity, or "weeping" flow from baffle126 also reduces the possibility that cavitation or bubble formationwill occur when a supersaturated fluid is delivered. As an example, atan ambient pressure of about 14.7 psi, an average blood pressure wouldbe approximately 18 psi. Atraumatic pressure would be in this generalrange, but high enough to create flow. Preferably, for most applicationswhere a pressure (and velocity) drop is required, the exit pressure willbe less than about 25 psi, and the exit velocity will be less than about200 cm/sec.

Such a pressure drop can be an important factor when high pressures areutilized with oxygen supersaturated perfusion treatments in order tomaintain the oxygen partial pressure at sufficient levels downstream ofa vessel-occluding procedure, such as balloon angioplasty. For example,in the delivery of oxygen supersaturated fluid according to thecopending applications incorporated by reference herein, utilizing thepresent invention, it could be necessary to apply pressures in excess ofabout 1000 psi (and potentially 10,000 to 15,000 psi or higher) toensure sufficient fluid flow and adequate oxygenation. As an example, aflow of about 35 ml per minute with perfusion of a supersaturated fluidas described in the above referenced applications can provideapproximately 2 cc of oxygen per minute downstream of the treatment sitein order to ensure a tissue oxygen partial pressure near acceptablelevels (sustainable vessel blood flow rates typically are about 25 to 35ml per minute in the large coronary arteries). Depending on theparticular application, flow rates may be as low as about 1 ml perminute. For coronary applications, flow rates between about 10 and 50 mlper minute may be used and more specifically approximately 25 to 35 mlper minute. Oxygen can thus be delivered at rates between about 2 to 10cc per minute and typically at least about 0.6 cc per minute. Utilizingthe present invention with oxygen supersaturated fluids as describedabove can provide an oxygen partial pressure downstream of an occludingtreatment site of at least about 750 mmHg and typically not less thanabout 1000 mmHg. Because of the high pressures that may be necessary tomaintain adequate oxygen supply, the components of the inventionpreferably have a burst strength of at least about 1000 psi or higher tomatch the anticipated maximum pressures.

As shown in FIG. 7, for example, porous baffle 126 is sealed topolyimide tube 54 so that no flow can bypass porous baffle 126. Porousbaffle 126 may be open or closed-ended, and preferably has length of atleast approximately 2 cm. However, the length of baffle 126 may betailored to suit the intended application, and it may be shorter thanperfusion zone 125. Baffle 126 may include a polyimide tube having aplurality of fluid exit ports, one or more layers of porouspolycarbonate or polyester tubing, or a combination of polyimide andpolycarbonate (or polyester) tubing within coil 116. These combinationswill be discussed further below.

FIGS. 9 and 10 show a baffle 126A including a perforated polyimide tube130. FIG. 10 is an enlarged view of the circled region 139 shown in FIG.9. Tube 130 is perforated with a plurality of exit ports 132. Exit ports132 may be formed with a laser, and are preferably each between 15-50 μmin diameter. Polyimide tubing 130 is surrounded by coil 116, whichsupports polyimide tube 130 and allows it to withstand high hydrostaticpressure. Polyimide tubing 130 may be bonded to polyimide tubing 54, orpolyimide tubing 130 may be a continuous part of tubing 54. In oneembodiment, the pressure of fluid exiting ports 132 causes theindividual windings of coil 116 to spread apart, so that fluid may bedelivered to a desired region. Alternatively, the windings of coil 116may be pre-tensioned, during the fabrication stage, to provide a fixedspacing between the windings of between 10 and 60 microns.

FIG. 9A illustrates a further alternative embodiment according to thepresent invention. The perfusion device illustrated in FIG. 9A utilizesa transitional region 20, as previously described in connection withFIG. 5, in combination with distal segment 40, as described above inconnection with FIG. 9.

Referring now to FIGS. 11 and 12, a perfusion guidewire including abaffle 126B is shown. FIG. 12 is an enlarged view of the circled region137 shown in FIG. 11. In baffle 126B, polyimide tube 54 is bonded,preferably with epoxy, to a rolled porous membrane, sheet, or tube 133having a first ply 134 and a second ply 136. A short tubular member 142(preferably made of polyimide) may also be used to bond polyimide tube54 to rolled porous membrane 133. Porous membrane 133 may be anyappropriate permeable material, including polyester and polycarbonate,or could be a screen or mesh of any appropriate material. A layer ofepoxy 144 can be used to bond porous membrane 133 and polyimide tube 54to tubular member 142. Plies 134 and 136 preferably have a 3 to 5 micronporosity, and are each about 6 microns thick. A single ply of porousmaterial could also be used if desired. Additional plies of porousmaterial will have the effect of further reducing the velocity of thedelivered perfusion fluid.

Again, fluid flows out from plies 134 and 136 and then passes throughthe windings of stainless steel coil 116. The coils of stainless steelcoil 116 may be spread apart by the hydrostatic pressure exerted by thefluid flowing from the porous membrane 133, or the windings of coil 116may be pre-tensioned, during the fabrication stage, to provide a fixedspacing between the windings of between 10 and 60 microns.

Referring now to FIGS. 7, 8, and 14, a perfusion guidewire including abaffle 126C is shown. FIG. 8 is an enlarged view of circled region 150shown in FIGS. 7 and 14. Baffle 126C preferably includes a first layerof perforated polyimide tubing 130 (including a plurality of exit ports132) and a rolled porous membrane, tube, or sheet 133, having a firstply 134 and a second ply 136. As was discussed above with respect to theother embodiments, polyimide tubing 54 may be bonded to tubing 130 andporous membrane 133 using epoxy alone, or epoxy in combination with aseparate tubular member. Tubing 130 may also form a part of tubing 54.The combination of the polyimide tube 130 with the porous membrane 133within coil 116 reduces the possibility that high velocity jets ofliquid will exit coil 116 during a perfusion procedure. Again, thisensures a low velocity, "weeping", atraumatic flow which minimizes thepossibility of cavitation or bubble formation during the delivery of theoxygen supersaturated fluid, which prevents recoil of catheter, andwhich minimizes the possibility of damaging, or causing trauma to nearbybody tissues.

Referring now to FIGS. 16 and 17, an alternative embodiment of aperfusion guidewire is shown. FIG. 17 is an enlarged view of circledregion 148 in FIG. 16. In FIGS. 16 and 17, polyimide tube 54 is bondedto tube 141 with a layer of epoxy 143. Tube 141 may be made of polyesterheat shrink tubing, polyimide tubing, or any other suitable material.Tube 141 has a plurality of perforations 145. Thus, baffle 126D ofperfusion region 125 is formed by tube 141 which fits over coil 116. Inoperation, fluid flows out of the windings of coil 116, and then out ofperforations 145. Again, windings of coil 116 may be forced apart by thehydrostatic pressure of the fluid being delivered, or the windings ofcoil 116 may be pre-tensioned during the fabrication stage.

Referring now to FIG. 18, another alternative embodiment of distalportion 40 of a perfusion guidewire according to the invention is shown.In the embodiment shown in FIG. 18, spring 116 extends out from thedistal end of tube 54 to solder joint 140. Spring 116 includes aperfusion region 125. A second, radiopaque platinum spring or distalcoil 42 extends from the distal end of spring 116. Coil 42 is fixed tospring 116 by solder joint 140.

In the embodiment shown in FIG. 18, core wire 24 preferably extends pastsolder joint 140, then tapers and terminates within distal coil 42. Astainless steel ribbon 208 is preferably mounted to the distal tip ofdistal coil 42. The proximal end of ribbon 208 is mounted to the sectionof core wire 24 just proximal to solder joint 140.

Perfusion region 125 includes a baffle 126E. Baffle 126E may take theform of baffles 126A-C, as discussed above with respect to FIGS. 9, 11,and 14. Baffle 126E may also take the form of any appropriateconfiguration that provides the desired fluid flow characteristics.Baffle 126E may be open- or close-ended, and may be any desired lengththat fits within perfusion region 125.

Modifications for Use in Angiography or Angioscopy Applications

As was discussed above, the present invention may be used to deliverrelatively large quantities of liquid to a desired location withoutcausing trauma to the surrounding tissues, and without causing recoil ofthe delivery device. The present invention further allows such largequantities of liquid to be delivered using a relatively low profile(i.e., small diameter) device.

In addition to its usefulness as a perfusion guidewire in angioplastyand similar procedures, the present invention is also well suited forthe procedures of angiography and angioscopy. In angiographicprocedures, the present invention could be used to deliver contrastmaterial to a site of interest; in angioscopic procedures, the presentinvention could be used to deliver saline to a site of interest. Again,saline in such procedures is used to displace blood, so that clearimages can be made of a vessel wall.

Embodiments of the present invention can be scaled so that appropriateamounts of liquid can be delivered to a desired location. In angiographyapplications, a perfusion device according to the present inventioncould have outside diameters ranging from about 0.5 mm to 3.0 mm(approximately 1.5 to 9 French), with an approximately 1.0 mm (3 French)diameter being the preferred size for both intra-coronary andintra-cerebral angiography applications. This size would accommodate thenecessary contrast material volumes for adequate vessel visualization,while assuring minimal invasiveness compared to commercially available,5 French or larger angiography catheters. Additionally, the guidewirebody and tip configuration properties of a perfusion device according tothe present invention enable fast and accurate device placement indifficult vessel geometries.

A preferred perfusion device can be connected to commercially available"power injectors" (such as those manufactured by MedRad, Inc. ofPittsburgh, Pa.), for high pressure, high volume contrast angiography.Because of the rugged construction of the preferred perfusion device, itcan tolerate pressures considerably greater than those tolerated bycommercially available angiography catheters. This should enable afuture generation of even higher pressure power injectors.

Finally, the small size of the perfusion device, compared tocommercially available catheters, enables outpatient angiography studiesbecause of the reduced puncture site size and associatedcomplications/concerns with the puncture/insertion site (typically inthe leg, arm, or neck).

In angioscopy procedures, a perfusion guidewire of the type discussedabove (preferably having an outside diameter of approximately 0.014", orabout 1 French) could be combined with the optical bundle of acommercially available angioscope.

Such a combination of a perfusion guidewire and an angioscope could bedelivered to a desired location using a 6 French guide catheter, insteadof the larger 8 French catheter currently required by the ImageCath®coronary angioscope discussed above. The high liquid flow rate permittedby the present invention would allow the generation of angioscopicimages of similar or better quality than those currently available.

Reconfigurable Fluid Delivery Device

In certain angiography or other applications, it may be desirable tochange the shape of the distal end of the fluid delivery device whilethe delivery device is in vivo. In such situations, the use of aperfusion guidewire or device of the type discussed above having fixedcore wire and a distal coil with a predefined shape may not provide thedesired ability to change shape in mid-procedure.

FIG. 19 shows an alternative embodiment of the present inventionincluding a reconfigurable fluid delivery device 220. Device 220includes a proximal segment 10 and a distal segment 222.

Proximal segment 10 includes an elongated tube 12 defining a lumen ofthe type discussed above with respect to FIG. 2. Again, tube 12 may be astainless steel tube coated with PTFE; tube 12 could also be a tube madeof polyimide, high density polyethylene, or any high strength polymer ormetal (including a non-porous metal spring or braided line) having theappropriate strength and other characteristics required for use during aparticular procedure. In angiography applications, tube 12 preferablyhas about a 3 French (approximately 1.0 mm) outside diameter.

Fluid delivery device 220 differs from the embodiments discussed abovein that there is no transitional region or fixed core wire included inthe device. As is shown in FIG. 20, distal segment 222 preferablyincludes a coil 116 which is attached to the distal end of tube 12. Theproximal end of coil 116 may be attached to the distal end of tube 12using any of the attachment techniques discussed above with respect tothe several alternative embodiments. Coil 116 may also be attached totube 12 using any other appropriate attachment technique. Portions ofcoil 116 may be radiopaque if desired.

As in the embodiments discussed above, distal segment 222 preferablyincludes a perfusion zone 125 and a baffle 126. In the embodiment shownin FIG. 20, distal segment 222 includes a baffle 126B of the typediscussed above with respect to FIGS. 11 and 12. However, distal segment222 could include a baffle 126A of the type discussed above with respectto FIGS. 9 and 10, a baffle 126C of the type discussed above withrespect to FIGS. 7 and 8, or any other appropriate baffle which providesthe desired reduction in fluid flow velocity. A removable stylet 224(shown in phantom) could be used to change the shape of the distalsegment 222. This feature will be discussed further below.

As is shown in FIG. 19, device 220 is preferably connected to Y-adapter226 via luer-lock connector 228, both of which are known to thoseskilled in the art. Contrast material or other desired liquid may bepumped into device 220 via port 230 in adapter 226. A stylet 224 may beinserted into device 220 via port 232 in adapter 226.

By advancing a stylet 224 with a predetermined size and shape throughdevice 220, the flexibility and shape of device 220 can be altered asneeded. During initial passage from a peripheral artery (for example,the radial, brachial, or femoral artery) to an arterial site ofinterest, distal segment 222 should be quite flexible. Accordingly, astylet 224 having little support should be inserted within the lumenchannel of device 220. After reaching the site of interest, the flexiblestylet may be replaced with one that provides a suitable shape andstiffness to facilitate engagement of the artery of interest. Forexample, a stylet having a shape similar to that used with preformedconventional coronary angiographic catheters could be advanced to thedistal end of device 220 into a coronary artery. With stylet 224 inplace, contrast material is injected through baffle 126 and into thesite of interest. After completion of injections for one coronary artery(or bypass graft), stylet 224 can be replaced with another one thatallows engagement of a different coronary artery or bypass graft.

Angioscopy Device

FIG. 21 shows a distal segment 40 of a preferred fluid delivery devicealong with an angioscopic optical bundle 250. Again, a perfusionguidewire or fluid delivery device of the type discussed above(preferably having an outside diameter of approximately 0.014" or about1 French) could be combined with the optical bundle of a commerciallyavailable angioscopic optical bundle. Such a combination of a perfusionguidewire or fluid delivery device and an angioscope could be deliveredto a desired location using a 6 French guide catheter 252, instead ofthe larger 8 French guide catheter currently required by the ImageCath®coronary angioscope discussed above. The high liquid flow rate permittedby the present invention would allow the generation of angioscopicimages of similar or better quality than those currently available.

In FIG. 21, the distal segment of the fluid delivery device or guidewireof FIG. 18 is shown. However, it will be understood that any of theembodiments discussed above could be used in an angioscopy application.Moreover, it will be understood that any appropriate image bundle 250having the desired size and imaging characteristics could be used incombination with the guidewire or fluid delivery device of the presentinvention.

The present invention has been described in terms of a preferredembodiment. The invention, however, is not limited to the embodimentdepicted and described. Rather, the scope of the invention is defined bythe appended claims.

What is claimed is:
 1. An angioscopy device, comprising:a guide catheter; an angioscopic viewing device; and a fluid delivery device; the viewing device and fluid delivery device at least partially contained within the guide catheter; wherein the fluid delivery device comprises: a flexible, high pressure tubular housing defining a fluid lumen therethrough, the tubular housing having a proximal end and a distal end; an elongated cylindrical sheath extending from the distal end of the tubular housing, the sheath defining a continuation of the fluid lumen; a coil extending along at least a portion of the cylindrical sheath; and a baffle zone extending along at least a portion of the coil, the baffle zone defining at least one fluid exit and comprising means for creating a flow velocity drop such that fluid perfused through said device leaves said fluid exit under atraumatic conditions.
 2. An angioscopy device, comprising:a guide catheter; an angioscopic viewing device; and a fluid delivery device; the viewing device and fluid delivery device at least partially contained within the guide catheter; wherein the fluid delivery device comprises: a tubular housing defining a fluid lumen therethrough, the housing having a proximal portion and a distal portion; the proximal portion of the tubular housing having a first outside diameter, and the distal portion of the tubular housing having a second outside diameter; a core wire having a proximal end and a distal end, the proximal end of the core wire being tapered and secured within the fluid lumen to a notch in the proximal portion of the tubular housing; a first coil mounted at the distal end of the core wire; and an elongated cylindrical sheath extending from the distal portion of the tubular housing over a portion of the core wire, the sheath defining a continuation of the fluid lumen and having at least one fluid exit in the form of a porous baffle.
 3. An angioscopy device, comprising:a guide catheter; an angioscopic viewing device at least partially disposed within the guide catheter; and a fluid delivery device at least partially disposed within the guide catheter, the fluid delivery device comprising: a tubular housing defining a fluid lumen therethrough, the housing having a proximal portion and a distal portion; a core wire having a proximal end and a distal end, the proximal end of the core wire being secured to the tubular housing; an elongated cylindrical sheath extending from the distal portion of the tubular housing, the sheath defining a continuation of the fluid lumen and having at least one fluid exit in the form of a porous baffle; a first coil mounted on the distal end of the core wire; a second coil extending along at least a portion of the porous baffle, wherein a distal end of the second coil is attached to a proximal portion of the first coil; and a stainless steel ribbon extending from a distal end of the second coil and along at least a portion of the first coil. 